This invention provides a means in dentistry to permanently record the various occlusal positions that occur when opposing teeth are brought together to make contact.
An occlusal position is formed when the surfaces of opposing teeth are brought together to make contact with one another. It is composed of occlusal contacts, near occlusal contacts, and non-contacts. An occlusal contact occurs with the touching of opposing teeth. Near occlusal and non-contacts are those spacial areas that are formed between opposing tooth surfaces that do not touch on closure. Dentists currently lack a reliable recording system for permanently recording the three components of an occlusal position.
A permanent record of an occlusal position would be useful in the diagnosis and treatment of various dental problems, as for example, diagnosis and treatment planning in periodontics, orthodontics and restorative dentistry. Such records could also be valuable for defending against the rising tide of assertions of dental malpractice, or for establishing malpractice. Other uses include (1) clinical diagnosis and longitudinal research, (2) identification procedures (no two recordings other than for the same person are alike), (3) temporomandibular joint determinations, and (4) dental laboratory communication such as in the fabrication of dental bridges and prosthetic replacements.
At present dentists evaluate occlusal positions using occlusal contact indicating media such as articulating paper, typewriter ribbon and articulating film. Patients close their teeth onto the indicating media which leaves marks on the teeth relating to the points of contact. The marks made in situ are then interpreted intraorally.
This technique has several drawbacks. Most significant, the markings produced are intended to be viewed intraorally at the time of the procedure. There is no provision for permanently recording the marks. Also, any mark transferred to the marking indicator itself cannot be permanently recorded; nor can the indicator itself be hygienically stored. A further drawback is that the markings produced do not always represent the actual pattern of contact points but are rather a by-product of the indicator used. There exists a wide range of variability between the occlusal contact markings produced by various indicators, all of which are used for the same purpose--to locate and define occlusal contacts. The indicators may alter the vertical dimension of occlusion which results in a pattern of contacts that differs from the pattern of contacts at an unaltered vertical dimension. This problem is exacerbated by the natural movement of the jaw. As the two rows of teeth are brought together, the back teeth may approach contact before the front teeth. Conventional indicators may act as a wedge between the two rows, preventing the teeth from reaching their normal occlusal position. This produces a false pattern of contacts. These indicators may also be forced between the teeth, thereby altering the horizontal dimension of occlusion, which results in a false pattern of contacts. Finally, these indicators are not capable of distinguishing between near contacts and non-contacts.
A variety of wax strips are currently in use to evaluate occlusal positions. Unlike indicating media such as typewriter ribbon, the markings produced by biting into the wax strips are intended to be viewed extraorally by visual inspection. Again, these wax strips are not intended for or capable of providing a hygienic permanent record of an occlusal position. These wax strips also do not provide any quantitative information about near contacts. Rough visual inspection does not allow for discriminating subtle differences between multiple measurements in the same individual before and after treatment or over time. Likewise, rough visual inspection is not sufficiently precise to serve as an identification tool. Finally, the markings produced by an individual vary widely with each product.
A recent advance in the area of analyzing occlusion is the process known as photo-occlusion. In this process, an articulating film is placed in the patient's mouth. Bringing opposing teeth together impresses a strain pattern in the "wafer." This strain pattern is caused by permanent local deformations of the wafer. After removing the wafer from the patient's mouth, the wafer is viewed on an expensive optical instrument. A strain pattern appears in colors with each color corresponding to a different strain intensity. This strain color phenomenon is due to the residual birefringence resulting from the permanent local deformations of the wafer. The strain pattern may then be permanently recorded by photographing the strain pattern.
While this system is an advance in the field of occlusion analysis, it fails to solve many of the problems of the prior art. First, photo-occlusion measures strain. In particular, it measures the forces which exist between opposed teeth as the two rows of teeth are closed upon the wafer. While such a measure may be correlated with occlusal contacts or the distance between teeth at near contact areas, it is at best just that, a correlation and does not accurately record the actual contact and near contact points. Second, the wafer alters the vertical dimension at closure due to its thickness and false markings will occur. Third, because the wafer offers resistance to closure, duplicate bite impressions may yield different results due to any variation in bite pressure. Furthermore, overcoming this resistance to closure may alter the horizontal dimension of the bite further producing a pattern that does not represent the actual or near occlusal contacts. Duplicating bite impressions against this resistance is particularly problematic where the measurements of young or feeble persons (or even deceased persons for identification purposes) are attempted. Finally, while this system offers one of the first methods for conveniently producing a permanent hygienic record of an occlusal position, it does so only at a substantial cost since expensive polariscopic equipment is required.
The applicant's invention overcomes these and other shortcomings.
It is an object of the invention to provide a system for examining an occlusal position at virtually an unaltered vertical dimension.
It is also an object of the invention to provide a system for examining an occlusal position at virtually an unaltered horizontal dimension.
It is a further object of the invention to provide a means for permanently documenting an occlusal position.
It is a further object of the invention to provide a means for permanently documenting an occlusal position at a relatively insubstantial expense.
It is a further object of the invention to provide a means for computerized analysis of an occlusal position.